The Self-Centering Action trucks self align themselves parallel with the car for easier placement on track.

Mounts with a #2 or 2-56 screw.

"HGC" or High Gravity Compound, weighs nearly the same as Metal Trucks but with more detail & a 2 piece split bolster design for more efficient truck equalization, reduced axle friction for greater rolling performance.

The term Code 110 and Code 88 relates to the width of the wheels and has no relationship to track code. Code 110 wheels are .110" wide and Code 88 are .088" wide. Code 110 wheels are the common (or "Standard") width wheels and Code 88 are what is called "Semi-Scale" and are used when the modeler wants a more prototypical looking wheel width. Actual HO-Scale prototypical wheel width would be around .067" wide and although they will run OK on the average track they will not go through common turnouts and crossings. Code 88 (.088") is just about the minimum width of wheel that will run on most standard or common track if gauged correctly. It really is a matter of appearances because there's very little operational differences between running Code 110 or Code 88 wheels. Code 88 wheels look really good and are most noticeable on open frame cars like hoppers and tank cars. However, they also look great on boxcars, gondolas, and reefers but not quite as noticeable. As mentioned above track code and wheel code have no relationship meaning Code 110 and Code 88 will run on most any code of track. Track code is simply the measured height of the rail, code 100 is .100" tall, code 83 is .083" tall, code 70 is .070" tall, and so on.